Techniques for forming self-aligned memory structures

ABSTRACT

Methods, systems, and devices for techniques for forming self-aligned memory structures are described. Aspects include etching a layered assembly of materials including a first conductive material and a first sacrificial material to form a first set of channels along a first direction that creates a first set of sections. An insulative material may be deposited within each of the first set of channels and a second sacrificial material may be deposited onto the first set of sections and the insulating material. A second set of channels may be etched into the layered assembly of materials along a second direction that creates a second set of sections, where the second set of channels extend through the first and second sacrificial materials. Insulating material may be deposited in the second set of channels and the sacrificial materials removed leaving a cavity. A memory material may be deposited in the cavity.

BACKGROUND

The following relates generally to a system that includes at least onememory device and more specifically to techniques for formingself-aligned memory structures.

Memory devices are widely used to store information in variouselectronic devices such as computers, wireless communication devices,cameras, digital displays, and the like. Information is stored byprogramming different states of a memory device. For example, binarydevices most often store one of two states, often denoted by a logic 1or a logic 0. In other devices, more than two states may be stored. Toaccess the stored information, a component of the device may read, orsense, at least one stored state in the memory device. To storeinformation, a component of the device may write, or program, the statein the memory device.

Various types of memory devices exist, including magnetic hard disks,random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM),synchronous dynamic RAM (SDRAM), ferroelectric RAM (FeRAM), magnetic RAM(MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM),other chalcogenide memory technologies and others. Memory devices may bevolatile or non-volatile. Improving memory devices, generally, mayinclude increasing memory cell density, increasing read/write speeds,increasing reliability, increasing data retention, reducing powerconsumption, or improving manufacturing processes, among other metrics.Improves solutions for saving space in the memory array, increasingmemory cell density, or manufacturing smaller memory cells for a memoryarray may be desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a memory device in accordance withexamples as disclosed herein.

FIG. 2 illustrates an example of a memory array that supports a memorydevice in accordance with examples as disclosed herein.

FIGS. 3-14 illustrate example operations performed as part of amanufacturing process that support techniques for forming self-alignedmemory structures in accordance with examples as disclosed herein.

FIGS. 15 and 16 show flowcharts illustrating a method or methods thatsupport techniques for forming self-aligned memory structures inaccordance with examples as disclosed herein.

DETAILED DESCRIPTION

It may be desirable to form smaller memory cells, for example, toincrease the storage density of a memory array, decrease powerconsumption per memory cell, decrease manufacturing costs, etc. However,process flows used in traditional manufacturing operations may not beable to reliably form memory cell features below a certain size. Forexample, etching a memory material to form smaller memory cells mayinclude removing sections of the memory material that are closertogether. As memory cell structures become smaller, secondary effectsfrom manufacturing processes (e.g., etch damage, material contamination,etc.) may have a greater impact on the structure and function of thefinal memory cell. Additionally, manufacturing memory cells mayincluding orienting a subsequent manufacturing process (e.g., a secondetch process) in relation to a prior manufacturing process (e.g., afirst etch process). As the memory cell size decreases, themanufacturing process may maintain greater tolerances between differentoperations. Accordingly, manufacturing processes that are used toproduce larger memory cells may cause damage to smaller memory cellssuch as contamination or erosion, which prevent these processes fromreliably forming memory cells at a smaller scale.

Processes for forming memory cells may include using a first maskingpattern to remove material from a layered assembly of materials thatincludes a first sacrificial material and does not include a memorymaterial. The voids left by removing material using the first maskingpattern may be filled with insulating material to form a first portionof the memory cell structure. A second sacrificial material may bedeposited onto the first portion of the memory cell structure and asecond masking pattern may be used to remove portions of both the secondsacrificial material and the first sacrificial material during the sameoperation. The voids left by removing the first sacrificial material andthe second sacrificial material may be filled with insulating materialthat forms a second portion of the memory cell. Accordingly, removingboth first and second sacrificial materials in a single operation alignsfeatures of the second portion of the memory cell structure with thefeatures of the first portion of the memory cell structure. Remainingportions of both the first and second sacrificial materials may beremoved to form a memory cavity.

After the insulating material has been formed and remaining portions ofthe sacrificial materials are removed, memory material may be depositedinto the cavities defined by the insulating material. In some cases,excess memory material may be removed and a second or top conductor maybe deposited onto the memory material. A bottom conductor may contact afirst group of memory cells along a first direction and a top conductormay contact a second group of memory cells along a second direction. Thetop conductor may partially fill the void created above the memorycavity by removing the first and second sacrificial materials.Accordingly, the manufacturing process may self-align the memorymaterial with structures such as the first/bottom conductor and thesecond/top conductor by using an operation that remove portions of botha first and second sacrificial materials in the same process step.

Features of the disclosure are initially described in the context ofmemory devices as described with reference to FIGS. 1-2. Features of thedisclosure are described in the context a manufacturing process asdescribed with reference to FIGS. 3-14. These and other features of thedisclosure are further illustrated by and described with reference toflowcharts that relate to techniques for forming self-aligned memorystructures as described with references to FIGS. 15-16.

FIG. 1 illustrates an example memory device 100 as disclosed herein.Memory device 100 may also be referred to as an electronic memoryapparatus. FIG. 1 is an illustrative representation of variouscomponents and features of the memory device 100. As such, it should beappreciated that the components and features of the memory device 100are shown to illustrate functional interrelationships, not their actualphysical positions within the memory device 100. In the illustrativeexample of FIG. 1, the memory device 100 includes a three-dimensional(3D) memory array 102. The memory array 102 includes memory cells 105that may be programmable to store different states. In some examples,each memory cell 105 may be programmable to store two states, denoted asa logic 0 and a logic 1. In some examples, a memory cell 105 may beconfigured to store more than two logic states. Although some elementsincluded in FIG. 1 are labeled with a numeric indicator, othercorresponding elements are not labeled, though they are the same orwould be understood to be similar, in an effort to increase visibilityand clarity of the depicted features.

The memory array 102 may include two or more two-dimensional (2D) memoryarrays 103 formed on top of one another. This may increase a quantity ofmemory cells that may be placed or created on a single die or substrateas compared with 2D arrays, which in turn may reduce production costs,or increase the performance of the memory device, or both. The memoryarray 102 may include two levels of memory cells 105 and may thus beconsidered a memory array; however, the quantity of levels is notlimited to two. Each level may be aligned or positioned so that memorycells 105 may be aligned (exactly, overlapping, or approximately) withone another across each level, forming a memory cell stack 145. In somecases, the memory cell stack 145 may include multiple memory cells laidon top of another while sharing a word line for both as explained below.In some cases, the memory cells may be multi-level memory cellsconfigured to store more than one bit of data using multi-level storagetechniques.

In some examples, each row of memory cells 105 is connected to a wordline 110, and each column of memory cells 105 is connected to a bit line115. The term access lines may refer to word lines 110, bit lines 115,or combinations thereof. Word lines 110 and bit lines 115 may beperpendicular (or nearly so) to one another and may create an array ofmemory cells. As shown in FIG. 1, the two memory cells 105 in a memorycell stack 145 may share a common conductive line such as a bit line115. That is, a bit line 115 may be in electronic communication with thebottom electrode of the upper memory cell 105 and the top electrode ofthe lower memory cell 105. Other configurations may be possible, forexample, a third layer may share a word line 110 with a lower layer. Ingeneral, one memory cell 105 may be located at the intersection of twoconductive lines such as a word line 110 and a bit line 115. Thisintersection may be referred to as a memory cell's address. A targetmemory cell 105 may be a memory cell 105 located at the intersection ofan energized access line 110 and bit line 115; that is, access line 110and bit line 115 may be energized (may have a voltage potential orcurrent flow) to read or write a memory cell 105 at their intersection.Other memory cells 105 that are in electronic communication with (e.g.,connected to) the same access line 110 or bit line 115 may be referredto as untargeted memory cells 105.

Electrodes may be coupled with a memory cell 105 and a word line 110 ora bit line 115. The term electrode may refer to an electrical conductor,and in some cases, may be employed as an electrical contact to a memorycell 105. An electrode may include a trace, wire, conductive line,conductive layer, or the like that provides a conductive path betweenelements or components of memory device 100. In some examples, a memorycell 105 may include a chalcogenide material positioned between a firstelectrode and a second electrode. One side of the first electrode may becoupled to a word line 110 and the other side of the first electrode tothe chalcogenide material. In addition, one side of the second electrodemay be coupled to a bit line 115 and the other side of the secondelectrode to the chalcogenide material. The first electrode and thesecond electrode may be the same material (e.g., carbon) or differentmaterials.

Operations such as reading and writing may be performed on memory cells105 by activating or selecting access line 110 and bit line 115. In someexamples, bit lines 115 may also be known digit lines 115. References toaccess lines, word lines, and bit lines, or their analogues, areinterchangeable without loss of understanding or operation. Activatingor selecting a word line 110 or a bit line 115 may include applying avoltage to the respective line. Word lines 110 and bit lines 115 may bemade of conductive materials such as metals (e.g., copper (Cu), aluminum(Al), gold (Au), tungsten (W), titanium (Ti)), metal alloys, carbon,conductively-doped semiconductors (e.g., polysilicon), or otherconductive materials, alloys, compounds, or the like.

Accessing memory cells 105 may be controlled through a row decoder 120and a column decoder 130. For example, a row decoder 120 may receive arow address from the memory controller 140 and activate the appropriateword line 110 based on the received row address. Similarly, a columndecoder 130 may receive a column address from the memory controller 140and activate the appropriate bit line 115. For example, memory array 102may include multiple word lines 110, labeled WL_1 through WL_M, andmultiple digit lines 115, labeled BL_1 through BL_N, where M and Ndepend on the array size. Thus, by activating a word line 110 and a bitline 115, e.g., WL_2 and BL_3, the memory cell 105 at their intersectionmay be accessed. As discussed below in more detail, accessing memorycells 105 may be controlled through a row decoder 120 and a columndecoder 130 that may include one or more doped materials that extend ina direction away from a surface of a substrate coupled to the memoryarray 102.

Upon accessing, a memory cell 105 may be read, or sensed, by sensecomponent 125 to determine the stored state of the memory cell 105. Forexample, a voltage may be applied to a memory cell 105 (using thecorresponding word line 110 and bit line 115) and the presence of aresulting current may depend on the applied voltage and the thresholdvoltage of the memory cell 105. In some cases, more than one voltage maybe applied. Additionally, if an applied voltage does not result incurrent flow, other voltages may be applied until a current is detectedby sense component 125. By assessing the voltage that resulted incurrent flow, the stored logic state of the memory cell 105 may bedetermined. In some cases, the voltage may be ramped up in magnitudeuntil a current flow is detected. In other cases, predetermined voltagesmay be applied sequentially until a current is detected. Likewise, acurrent may be applied to a memory cell 105 and the magnitude of thevoltage to create the current may depend on the electrical resistance orthe threshold voltage of the memory cell 105.

In some examples, a memory cell may be programmed by providing anelectric pulse to the cell, which may include a memory storage element.The pulse may be provided via a first access line (e.g., word line 110)or a second access line (e.g., bit line 115), or a combination thereof.In some cases, upon providing the pulse, ions may migrate within thememory storage element, depending on the polarity of the memory cell105. Thus, a concentration of ions relative to the first side or thesecond side of the memory storage element may be based at least in parton a polarity of a voltage between the first access line and the secondaccess line. In some cases, asymmetrically shaped memory storageelements may cause ions to be more crowded at portions of an elementhaving more area. Certain portions of the memory storage element mayhave a higher resistivity and thus may give rise to a higher thresholdvoltage than other portions of the memory storage element. Thisdescription of ion migration represents an example of a mechanism of thememory cell for achieving the results described herein. This example ofa mechanism should not be considered limiting. This disclosure alsoincludes other examples of mechanisms of the memory cell for achievingthe results described herein.

Sense component 125 may include various transistors or amplifiers todetect and amplify a difference in the signals, which may be referred toas latching. The detected logic state of memory cell 105 may then beoutput through column decoder 130 as output 135. In some cases, sensecomponent 125 may be part of a column decoder 130 or row decoder 120.Or, sense component 125 may be connected to or in electroniccommunication with column decoder 130 or row decoder 120. The sensecomponent may be associated either with column decoder or row decoder.

A memory cell 105 may be set or written by activating the relevant wordline 110 and bit line 115 and at least one logic value may be stored inthe memory cell 105. Column decoder 130 or row decoder 120 may acceptdata, for example input/output 135, to be written to the memory cells105. In the case of a memory cell including a chalcogenide material, amemory cell 105 may be written to store a logic state in the memory cell105 by applying a first voltage to the memory cell 105 as part of theaccess operation based on coupling the first conductive line of thedecoder (e.g., row decoder 120 or column decoder 130) with the accessline (e.g., word line 110 or bit line 115).

The memory controller 140 may control the operation (e.g., read, write,re-write, refresh, discharge) of memory cells 105 through the variouscomponents, for example, row decoder 120, column decoder 130, and sensecomponent 125. In some cases, one or more of the row decoder 120, columndecoder 130, and sense component 125 may be co-located with the memorycontroller 140. Memory controller 140 may generate row and columnaddress signals to activate the desired word line 110 and bit line 115.Memory controller 140 may also generate and control various voltages orcurrents used during the operation of memory device 100.

The memory controller 140 may be configured to select the memory cell105 by applying a first voltage to the first conductive line of thedecoder (e.g., row decoder 120 or column decoder 130). In some cases,the memory controller 140 may be configured to couple the firstconductive line of the decoder with a word line (e.g., word line 110 orbit line 115) associated with the memory cell 105 based on selecting thememory cell 105. The memory controller 140 may be configured to applythe first voltage to the memory cell 105 based at least in part oncoupling the first conductive line of the decoder with the access line.

In some examples, the memory controller 140 may be configured to apply asecond voltage to a second conductive line of the decoder as part of theaccess operation. In some cases, the second voltage may cause the dopedmaterial to selectively couple the first conductive line of the decoderwith the access line associated with the memory cell 105. Applying thefirst voltage to the memory cell 105 may be based on applying the secondvoltage to the second conductive line. For example, the memorycontroller 140 may select the memory cell 105 based on an intersectionof the first voltage and the second voltage. In some cases, a signalapplied to the memory cell 105 as part of the access operation may havea positive polarity or a negative polarity.

In some examples, the memory controller 140 may receive a commandcomprising an instruction to perform the access operation on the memorycell 105 and identify an address of the memory cell 105 based onreceiving the command. In some cases, applying the second voltage to thesecond conductive line may be based on identifying the address. If theaccess operation is a read operation, the memory controller 140 may beconfigured to output a logic state stored in the memory cell 105 basedon applying the first voltage to the memory cell 105. If the accessoperation is a write operation, the memory controller 140 may beconfigured to store a logic state in the memory cell 105 based onapplying the first voltage to the memory cell 105. Although discussed asapplied by using a first voltage and a second voltage, it should beunderstood that current may be applied between the first conductive lineand second conductive line to perform the access, operation, in somecases.

FIG. 2 illustrates an example of a memory array that supports a memorydevice 200 in accordance with examples as disclosed herein. Memorydevice 200 may be an example of portions of memory array 102 describedwith reference to FIG. 1. Memory device 200 may include a first array ordeck 205 of memory cells that is positioned above a substrate 204 andsecond array or deck 210 of memory cells on top of the first array ordeck 205. Memory device 200 may also include word line 110-a and wordline 110-b, and bit line 115-a, which may be examples of word line 110and bit line 115, as described with reference to FIG. 1. Memory cells ofthe first deck 205 and the second deck 210 each may have one or morememory cell (e.g., memory cell 220-a and memory cell 220-b,respectively). Although some elements included in FIG. 2 are labeledwith a numeric indicator, other corresponding elements are not labeled,though they are the same or would be understood to be similar, in aneffort to increase visibility and clarity of the depicted features.

Memory cells of the first deck 205 may include first electrode 215-a,memory cell 220-a (e.g., including chalcogenide material), and secondelectrode 225-a. In addition, memory cells of the second deck 210 mayinclude a first electrode 215-b, memory cell 220-b (e.g., includingchalcogenide material), and second electrode 225-b. The memory cells ofthe first deck 205 and second deck 210 may, in some examples, havecommon conductive lines such that corresponding memory cells of eachdeck 205 and 210 may share bit lines 115 or word lines 110 as describedwith reference to FIG. 1. For example, first electrode 215-b of thesecond deck 210 and the second electrode 225-a of the first deck 205 maybe coupled to bit line 115-a such that bit line 115-a is shared byvertically adjacent memory cells. In accordance with the teachingsherein, a decoder may be positioned above or below each deck if thememory device 200 includes more than one deck. For example, a decodermay be positioned above first deck 205 and above second deck 210. Insome cases, the memory cells 220 may be examples of phase-change memorycells or self-selecting memory cells.

The architecture of memory device 200 may be referred to as across-point architecture, in which a memory cell is formed at atopological cross-point between a word line and a bit line asillustrated in FIG. 2. Such a cross-point architecture may offerrelatively high-density data storage with lower production costscompared to other memory architectures. For example, the cross-pointarchitecture may have memory cells with a reduced area and, resultantly,an increased memory cell density compared to other architectures. Forexample, the architecture may have a 4F2 memory cell area, where F isthe smallest feature size, compared to other architectures with a 6F2memory cell area, such as those with a three-terminal selectioncomponent. For example, DRAM may use a transistor, which is athree-terminal device, as the selection component for each memory celland may have a larger memory cell area compared to the cross-pointarchitecture.

While the example of FIG. 2 shows two memory decks, other configurationsare possible. In some examples, a single memory deck of memory cells maybe constructed above a substrate 204, which may be referred to as atwo-dimensional memory. In some examples, a three or four memory decksof memory cells may be configured in a similar manner in athree-dimensional cross point architecture.

In some examples, one or more of the memory decks may include a memorycell 220 that includes chalcogenide material. The memory cell 220 may,for example, include a chalcogenide glass such as, for example, an alloyof selenium (Se), tellurium (Te), arsenic (As), antimony (Sb), carbon(C), germanium (Ge), and silicon (Si). In some examples, a chalcogenidematerial having primarily selenium (Se), arsenic (As), and germanium(Ge) may be referred to as SAG-alloy. In some examples, SAG-alloy mayinclude silicon (Si) and such chalcogenide material may be referred toas SiSAG-alloy. In some examples, the chalcogenide glass may includeadditional elements such as hydrogen (H), oxygen (O), nitrogen (N),chlorine (Cl), or fluorine (F), each in atomic or molecular forms.

In some examples, a memory cell 220 including chalcogenide material maybe programmed to a logic state by applying a first voltage or a firstcurrent. By way of example, when a particular memory cell 220 isprogramed, elements within the cell may separate, causing ion migration.Ions may migrate towards a particular electrode, depending on thepolarity of the voltage applied to the memory cell. For example, in amemory cell 220, ions may migrate towards the negative electrode. Thememory cell may then be read by applying a voltage across the cell tosense. The threshold voltage seen during a read operation may be basedon the distribution of ions in the memory cell and the polarity of theread pulse.

For example, if a memory cell has a given distribution of ions, thethreshold voltage detected during the read operation may be differentfor a first read voltage with a first polarity than it is with a secondread voltage having a second polarity. Depending on the polarity of thememory cell, this concentration of migrating ions may represent a logic“1” or logic “0” state. This description of ion migration represents anexample of a mechanism of the memory cell for achieving the resultsdescribed herein. This example of a mechanism should not be consideredlimiting. This disclosure is also applicable to other examples ofmechanisms of the memory cell for achieving the results describedherein.

In some cases, a first voltage may be applied to a first conductive lineof a decoder as part of an access operation of the memory cell 220. Uponapplying the first voltage, the first conductive line may be coupledwith the access line (e.g., word line 110-a, word line 110-b, or bitline 115-a) associated with the memory cell 220. For example, the firstconductive line may be coupled with the access line based on a dopedmaterial of the decoder which extends between the first conductive lineand the access line in a first direction.

In some examples, the first voltage may be applied to the memory cell220 based on coupling the first conductive line of the decoder with theaccess line. The decoder may include one or more doped materials thatextend between the first conductive line and the access line of thememory device 200 of memory cells in a first direction away from asurface of the substrate 204. In some cases, the decoder may be coupledwith the substrate 204.

FIGS. 3-15 illustrate a manufacturing process that includes performing aseries of operations on a layered assembly of materials to form one ormore memory cells of a memory array. These figures illustrate examplesof intermediate structures that may be formed by performing operationsof the manufacturing process on a layered assembly of materials. Thestructures illustrated in FIGS. 3-15 provide an example of a sequence ofoperations for the manufacturing process. In other cases, themanufacturing process may include combining various operations, alteringthe sequence of operations, eliminating one or more operations or stepsof these operations, or any combination thereof.

FIG. 3 illustrates top and cross-sectional views of a layered assemblyof materials 300 that supports techniques for forming self-alignedmemory structures in accordance with examples as disclosed herein. Thelayered assembly of materials 300 may include a substrate 302, which maybe an example of substrate 204 described with reference to FIG. 2., afirst conductive material 305, an electrode 310, a first sacrificialmaterial 315 and a first mask material 320. The layered assembly ofmaterials 300 may undergo one or more manufacturing processes to formmemory cells of a memory array, such as memory array 102 and memorydevice 200 described with reference to FIGS. 1 and 2.

The layered assembly of materials 300 may include a layer of conductivematerial 305 deposited onto or coupled with the substrate 302. The layerof conductive material 305 may undergo one or more manufacturingprocesses to form conductive lines of a memory array. For example, thelayer of conductive material 305 may be etched to form word lines forone or more memory cells, such as word lines 110 described withreference to FIGS. 1 and 2. In some cases, the conductive material 305may form a single continuous layer of the layered assembly of materials300 and one or more manufacturing processes (e.g., etching) may beperformed to form the layer of conductive material 305 into multiplediscrete structures of a memory array (e.g., series of parallel wordlines). In other examples, the conductive material 305 may be depositedor formed on the substrate 302 in a pattern to form one or morestructures (e.g., conductive lines/paths) within the layered assembly ofmaterials 300.

The layered assembly of materials 300 may include an electrode 310coupled with the conductive material 305. The electrode 310 may form alayer of material coupled with a surface, such as the top surface, ofthe conductive material 305. The electrode 310 may be an example ofelectrodes 215 or 225 described with reference to FIG. 2. The electrode310 may form a first contact with a memory material or memory cell ofthe memory array. In some cases, the electrode 310 layer may form asingle continuous layer of material over the conductive material 305. Inother cases, the electrode 310 may be deposited or formed on theconductive material 305 in a pattern to form one or more structures(e.g., electrode contacts) within the layered assembly of materials 300.In some cases, a pattern of the electrode 310 may match or correspond toa pattern of the conductive material 305.

The layered assembly of materials 300 may include a layer of firstsacrificial material 315 deposited onto or coupled with the electrode310. The first sacrificial material 315 may be used during one or moremanufacturing steps for forming one or more structures of the array. Insome cases, one or more portions of the first sacrificial material 315may be removed at different steps in the manufacturing process. Forexample, in a first operation a first portion of the first sacrificialmaterial 315 may be etched away to form cavities that are filled withinsulative material and in a second operation a second portion of thefirst sacrificial material may be removed exposing a cavity that isfilled with a memory material that forms a memory cell (e.g., memorycells 105 and 220 as described with reference to FIGS. 1 and 2).

A first mask material 320 may form a top surface of the layered assemblyof materials 300. In some cases, the first mask material 320 may beapplied to or formed over the sacrificial material 315 according to afirst pattern. For example, the first mask material 320 may be include ahard mask and be patterned using a photolithography process. In somecases, photoresists may be used alone as the first mask material 320 orto pattern a hard mask material. Patterning of the first mask material320 may include removing or defined portions from the first maskmaterial. For example, a photolithography process may be used to form afirst mask pattern that has pattern segments 325 for forming a first setof channels along a first direction (e.g., y-axis) in the layeredassembly of materials.

The sacrificial material 315 may be chosen based on its interaction toone or more manufacturing processes. For example, the sacrificialmaterial 315 may be a material that maintains desired dimensionaltolerances or behaves predictably and repeatably to specific processesoperations (e.g., etch, photolithography, etc.). That is, in cases wherea stack of material includes a memory material instead of thesacrificial material 315, an etch process may degrade, damage or changethe structure (e.g., surface chemistry) of the memory material. As thesize of memory cells shrink, these manufacturing induced defects maylimit the minimum size of a memory cell. For example, as memory cellsget smaller the manufacturing induced defects may comprise a largerpercentage of the total memory cell size and may result in memory cellsthat cannot reliably store data, for example, within one or morespecifications (e.g., time, temperature). However, using the sacrificialmaterial 315 may reduce contamination, degradation or changes in surfacechemistry of a memory material. For example, using a sacrificialmaterial may allow a memory material to be deposited onto the stack ofmaterial after one or more manufacturing operations are performed usingthe sacrificial material. Further, because the sacrificial material willbe removed, and is not used to store or read memory states, thesacrificial material 315 may be chosen to provide manufacturingadvantages such as greater dimensional stability during one or moremanufacturing operations (e.g., etching or depositing insulativematerial as described herein). In some cases, the sacrificial materialmay include a silicon nitride material.

The layered assembly of materials 300 may be used to form multiplememory cells of a memory array. In some cases, for example in 3D memorystructures, a first set/layer of memory cells may be formed from a firstlayered assembly of material 300 and a second set/layer of memory cellsmay be formed on top of the first set/layer by depositing a secondlayered assembly of materials 300 onto the first set of memory cells. Insome cases, a second or subsequent layer of memory cells may be formedby depositing a second layered assembly of material 300 in a differentdirection than a first layered assembly of material 300. For example,the second layered assembly of materials 300 may be deposited or formedat an orthogonal orientation to the first layered assembly of materials300. In some cases, a second or subsequent layered assembly of materials300 may have fewer or different layers, materials or materialcompositions as compared to the first layered assembly of materials 300.For example, a second layered assembly of material 300 may not includethe substrate 302, have a different conductive material 305, differentelectrode 310, different sacrificial material 315, different ordering ofthe layers (e.g., electrode 310 below the conductive material 305), orany combination thereof.

FIG. 4 illustrates top and cross-sectional views of an example of afirst structure 400 formed by a material removal operation as part of amanufacturing process for forming self-aligned memory structures inaccordance with examples as disclosed herein. The material removaloperation may be performed on the layered assembly of materials 300 toform the first structure 400, and after performing the material removaloperation on the layered assembly of materials 300, the first structure400 may include multiple first sections 425 forming one or more firstchannels 430.

The material removal operation may include etching the layered assemblyof materials 300 to remove defined portions that create first sections425 and first channels 430. The operation may include using a patternedmask (e.g., hard mask, photoresist, etc. described with reference toFIG. 3) to etch the first channels 430. Each first channel 430 may bedefined by or bounded by two of the first sections 425. For example,first channel 430-a may be formed by etching away a portion of thelayered assembly of materials 300, and have first section 425-a forminga first side of the channel and first section 425-b forming a secondside of the channel.

The etching operation may form multiple first sections 425 and multiplefirst channels 430. Each first section 425 may include a portion of thelayered assembly of materials. For example, each first section 425 mayinclude a first conductive material 405, an electrode 410, a firstsacrificial material 415 and a first mask material 420, which may beexamples of the first conductive material 305, the electrode 410, thefirst sacrificial material 315 and the first mask material described inrelation to FIG. 3. The first sections 425 may create a repeatingpattern of first channels 430 across the array. In some cases, eachfirst section 425 and each first channel 430 may extend in a firstdirection (along the y-axis).

FIG. 5 illustrates top and cross-sectional views of an example of asecond structure 500 formed by a material addition operation as part ofa manufacturing process for forming self-aligned memory structures inaccordance with examples as disclosed herein. The material additionoperation may be performed on the first structure 400 to form the secondstructure 500, and after performing the material addition operation onthe first structure 400, the second structure 500 may include multiplefirst sections 525 of the layered assembly of materials 300, which maybe examples of first sections 425 described with reference to FIG. 4.The second structure may also include insulating material 530 formingmultiple first insulative sections 535.

The material addition operation may include depositing an insulatingmaterial 530 into the first channels 430 formed by the previous etchingoperation. In some cases, the deposition operation may fill the firstchannels 430 with the insulating material 530 and excess insulatingmaterial 530 may cover a top surface of the first structure 400. Aplanarization procedure may be performed after depositing the insulatingmaterial 530 to expose a top surface of the first sections 525. As aresult, the second structure 500 may include an alternating sequence offirst sections 525 and first insulative sections 535. In some examples,the planarization process may create a substantial flat top surface onthe second structure 500, including an alternating sequence of a firstmask material and the insulating material 530. The insulating material530 may be, for example silicon dioxide.

FIG. 6 illustrates top and cross-sectional views of an example of athird structure 600 formed by a mask removal operation as part of amanufacturing process for forming self-aligned memory structures inaccordance with examples as disclosed herein. The mask removal operationmay be performed on the second structure 500 to form the third structure600, and after performing the mask removal operation on the secondstructure 500, the third structure 600 may include multiple firstsections 625 that include a first sacrificial material 615 as a toplayer. The first sacrificial material may be an example of the firstsacrificial materials 315, 415 described in relation to FIGS. 3-4. Thesecond structure may also include insulating material 630 formingmultiple first insulative sections 635, which may be examples ofinsulating material 530 and insulative sections 535 described withreference to FIG. 5.

The mask removal operation may include exposing a top surface of thefirst sacrificial material 615 and the third structure 600 may includean alternating sequence of first sections 625 and first insulativesections 635. Accordingly, the top surface of the third structure 600may include alternating sections of the first sacrificial material 615and the insulating material 630. In some examples, the mask removalprocess may be performed to produce a substantially flat top surface.For example, the mask removal process may include chemical mechanicalplanarization.

FIG. 7 illustrates top and cross-sectional views of an example of afourth structure 700 formed by a material addition operation as part ofa manufacturing process for forming self-aligned memory structures inaccordance with examples as disclosed herein. The material additionoperation may be performed on the third structure 600 to form the fourthstructure 700, and after performing the material addition operation onthe third structure 600, the fourth structure 700 may include a layer ofa second sacrificial material 720 and a layer of second mask material725. The second sacrificial material 720 may be deposited onto the topsurface of the third structure 600 and the second mask material 725 maybe deposited onto a top surface of the second sacrificial material 720.

The fourth structure 700 may include a layer of second sacrificialmaterial 720 deposited onto or coupled with the top surface of the thirdstructure 600 (e.g., first sacrificial material 615 and insulatingmaterial 630). The second sacrificial material 720 may be used duringone or more manufacturing steps for forming one or more structures ofthe array. In some cases, one or more portions of the second sacrificialmaterial 720 may be removed at different steps in the manufacturingprocess. For example, in a subsequent operation a first portion of thesecond sacrificial material 720 may be etched away to form cavities thatare filled with insulative material. In some cases, a second subsequentoperation may be performed to remove a second portion of the secondsacrificial material 720 to expose/create a cavity that is filled with amemory material and forms a memory cell (e.g., memory cells 105 and 220as described with reference to FIGS. 1 and 2).

A second mask material 725 may form a top surface of the fourthstructure 700. In some cases, the second mask material 725 may beapplied to or formed over the second sacrificial material 720 accordingto a second pattern. For example, the second mask material 725 mayinclude a hard mask and be patterned using a photolithography process.In some cases, a photoresist may be used as the second mask material 725or to pattern a hard mask material. Patterning of the second maskmaterial 725 may include removing defined portions from the second maskmaterial 725. For example, a photolithography process may be used toform a second mask pattern that has second pattern segments 730 forforming a second set of channels along a second direction (e.g., x-axis)in the fourth structure 700. The second pattern segments 730 may beoriented in a second direction that is a different orientation ascompared to the first direction discussed herein. For example, thesecond pattern segments 730 may be oriented at an orthogonalrelationship to the first pattern segments 325, described with relationto FIG. 3.

FIG. 8 illustrates top and cross-sectional views of an example of afifth structure 800 formed by a material removal operation as part of amanufacturing process for forming self-aligned memory structures inaccordance with examples as disclosed herein. The fifth structure mayinclude an electrode material 810, a first sacrificial material 815, asecond sacrificial material 820 and a second mask material 825, whichmay be examples of the electrode, the first sacrificial material, thesecond sacrificial material, and mask material described herein. Thematerial removal operation may be performed on the fourth structure 700to form the fifth structure 800, and after performing the materialremoval operation on the fourth structure 700, the fifth structure 800may include multiple second sections 827 forming one or more secondchannels 830.

The material removal operation may include etching through portions ofthe second sacrificial material 820 and the first sacrificial material815 of the fourth structure 700 to create second channels 830. Theoperation may include using a second mask pattern (e.g., hard mask,photoresist, etc.) oriented in the second direction to form the secondchannels 830. Accordingly, the second channels 830 may be oriented in adifferent direction as compared to the first channels 430. By etchingthe second channels 830 through both the first sacrificial material 815and the second sacrificial material 820, the second channels 830 mayself-align with features formed in the prior manufacturing operationsdescribed herein. For example, the second channels 830 may automaticallyalign cavities for the memory material with the bottom electrode 810.

The etching operation may form multiple second sections 827 and multiplesecond channels 830. Each second section 827 may include a portion ofthe fourth structure 700. For example, each second section 827 mayinclude a layer of first sacrificial material 815, a layer of secondsacrificial material 820, and a layer of a second mask material 825,which may be examples of the first sacrificial material, secondsacrificial material, and second mask material described herein. Thesecond sections 827 may create a repeating pattern of second channels830 across the fifth structure 800. In some cases, each second section827 and each second channel 830 may extend in the second direction(e.g., along or parallel to the x-axis).

Section view XII-XII illustrates an example of the structures forming abottom surface of each second channel 830. For example, the bottomsurface of the second channel 830 may include an alternating sequence ofelectrode sections 810 and first insulating material sections 835. Insome cases, the insulating material sections 835 may be taller or extendhigher than the electrode sections 810. Additionally or alternatively,both the electrode sections 810 and the insulating material sections 835may extend across the array in the first direction (along or parallel tothe y-axis).

FIG. 9 illustrates top and cross-sectional views of an example of asixth structure 900 formed by a material addition operation as part of amanufacturing process for forming self-aligned memory structures inaccordance with examples as disclosed herein. The material additionoperation may be performed on the fifth structure 800 to form the sixthstructure 900, and after performing the material addition operation onthe fifth structure 800, the sixth structure 900 may include multiplesecond sections 927 and multiple second insulative sections 935.

The material addition operation may include depositing an insulatingmaterial into the second channels 830 formed in the fifth structure 800by the previous etching operation. In some cases, the depositionoperation may fill the second channels 830 with the insulating materialand excess insulating material may cover a top surface of the fifthstructure 800. A planarization procedure (e.g., chemical mechanicalplanarization) may be performed after depositing the insulating materialto expose a top surface of the second sections 927. As a result, thesixth structure 900 may include an alternating sequence of secondsections 927 and second insulative sections 935. In some examples, theplanarization process may remove the second mask material and create asubstantial flat top surface on the sixth structure 900, which mayinclude an alternating sequence of a second sacrificial material and theinsulating material.

FIG. 10 illustrates top and cross-sectional views of an example of aseventh structure 1000 formed by a sacrificial material removaloperation as part of a manufacturing process for forming self-alignedmemory structures in accordance with examples as disclosed herein. Thesacrificial material removal operation may be performed on the sixthstructure 900 to form the seventh structure 1000, and after performingthe sacrificial material removal operation on the sixth structure 900,the seventh structure 1000 may include multiple second insulativesections 1035 and multiple third channels 1030 each having multiplememory cavities 1050.

Removing the first and second sacrificial materials from the sixthstructure may form/expose third channels 1030, which may extend alongthe second direction. As shown in section view XV-XV, each third channel1030 may be formed between two second insulative sections 1035. Forexample, third channel 1030-a may be formed by second insulative section1035-a on one side and second insulative section 1035-b on the otherside. A bottom of each third channel 1030 may include both electrodesections and first insulative sections. In each third channel 1030,memory cavities 1050 may be formed between first insulative sections1025. For example, as shown in section view XVI-XVI, a first memorycavity 1050-a may be formed between two first insulative sections1025-a, 1025-b. In some cases, an electrode may form a bottom surface ofthe memory cavity 1050. Accordingly, each memory cavity 1050 may beformed between first insulative sections 1025 and second insulativesections 1035. Further, the first insulative sections 1025 and thesecond insulative sections 1035 may have different heights. For example,the final memory array, may include memory material that is filled tothe height of the first insulative sections 1025. Thereby, a portion ofthe third channel 1030 above the memory cavities 1050 may include a topelectrode that extends along the second direction (e.g., orthogonal tothe direction of the bottom electrode of the layered assembly ofmaterials 300).

FIG. 11 illustrates top and cross-sectional views of an example of aneighth structure 1100 formed by memory material depositing operation aspart of a manufacturing process for forming self-aligned memorystructures in accordance with examples as disclosed herein. The memorymaterial depositing operation may be performed on the seventh structure1000 to form the eighth structure 1100, and after performing the memorymaterial depositing operation on the seventh structure 1000, the eighthstructure 1100 may include memory material 1155 filling each memorycavity 1050 (FIG. 10), and in some cases, at least a portion of thethird channels 1030 (FIG. 10).

The memory material deposition operation may include depositing achalcogenide memory material onto the seventh structure 1000. In somecases, the memory material may fill the third channels 1030 (FIG. 10)and cover a top surface of the second insulative sections 1035 (FIG.10). An etch or selective etch procedure may be performed to removeexcess memory material from the eighth structure 1100. In otherexamples, a selective memory material deposition procedure may beperformed, such that the memory material fills the memory cavities 1050(FIG. 10) to a height of the first insulative sections 1025 (FIG. 10).In some cases, a selective deposition procedure may not include asubsequent etch procedure to remove excess memory material. In othercases, an etch procedure, a polishing procedure or a combination thereofmay be performed to remove excess material or create desired surfaceproperties of the memory material. They etch and/or polishing proceduresmay be performed on the selectively deposited memory material, to removeexcess material from the eighth structure, or a combination thereof.

FIG. 12 illustrates top and cross-sectional views of an example of aninth structure 1200 formed by an etch operation as part of amanufacturing process for forming self-aligned memory structures inaccordance with examples as disclosed herein. The etch operation may beperformed on the eighth structure 1100 to form the ninth structure 1200,and after performing the etch operation on the eighth structure 1100,the ninth structure 1200 may include memory material filling each memorycavity 1050 (FIG. 10) to a height of the first insulative sections 1025(FIG. 10) to form memory cells 1240. As illustrated in the top andcross-sectional views (Section XIX-XIX and Sections XX-XX) a firstmemory cell 1420-a may be positioned between two first insulativesections 1225 having a first height and two second insulative sections1235 having a second height. First insulative section 1225 and secondinsulative sections 1235 may be examples of insulative sections formedfrom insulating material as described herein. Alternatively, the ninthstructure 1200 may be formed by selectively depositing a memory material1240 into the memory cavities 1050 formed by the insulative sections1025 and 1035 in the seventh structure (e.g., selectively depositingwhere the electrode material is exposed in the seventh structure), asdiscussed above.

FIG. 13 illustrates top and cross-sectional views of an example of atenth structure 1300 formed by an electrode depositing operation as partof a manufacturing process for forming self-aligned memory structures inaccordance with examples as disclosed herein. The electrode depositingoperation may be performed on the ninth structure 1200 to form the tenthstructure 1300, and after performing the electrode depositing operationon the ninth structure 1200, the tenth structure 1300 may include anelectrode material 1360 covering memory material in each memory cavity1250 (FIG. 12).

In some cases, the electrode material 1360 may be deposited across a topsurface of the ninth structure 1200. In these cases, the both the memorymaterial and insulating materials may be coated by the electrodematerial 1360. That is, the electrode material may form a continuouslayer across the top surface of the tenth structure 1300.

FIG. 14 illustrates top and cross-sectional views of an example of aneleventh structure 1400 formed by a conductor depositing operation aspart of a manufacturing process for forming self-aligned memorystructures in accordance with examples as disclosed herein. Theconductor depositing operation may be performed on the tenth structure1300 to form the eleventh structure 1400, and after performing theconductor depositing operation on the tenth structure 1300, the eleventhstructure 1400 may include a second conductor material 1465 filling atop portion of the third channels 1030 (FIG. 10).

The second conductive material 1465 may be deposited onto the tenthstructure 1300 to fill the portion of the third channels 1030 (FIG. 10)above the memory material and first insulative sections 1025 (FIG. 10).In some cases, the second conductive material may fill the thirdchannels 1030 and cover a top surface of the tenth structure 1300. Anetch or planarization procedure (e.g., chemical mechanicalplanarization) may be performed to remove the excess section conductivematerial 1465. Accordingly, the eleventh structure 1400 may includealternating sections of insulating material (e.g., second insulativesections 1235) and the second conductor material 1465.

FIG. 15 shows a flowchart illustrating a method or methods 1500 thatsupports techniques for forming self-aligned memory structures inaccordance with the present disclosure. The operations of method 1500may be implemented by a manufacturing system or one or more controllersassociated with a manufacturing system. In some examples, one or morecontrollers may execute a set of instructions to control one or morefunctional elements of the manufacturing system to perform the describedfunctions. Additionally or alternatively, one or more controllers mayperform parts of the described functions using special-purpose hardware.

At 1505, the method 1500 may include etching a first set of channelsalong a first direction into a layered assembly of materials to create afirst set of sections of the layered assembly of materials, the layeredassembly of materials including a first conductive material and a firstsacrificial material. The operations of 1505 may be performed accordingto the methods described herein.

At 1510, the method 1500 may include depositing an insulating materialwithin each of the first set of channels. The operations of 1510 may beperformed according to the methods described herein.

At 1515, the method 1500 may include depositing a second sacrificialmaterial onto the first set of sections of the layered assembly ofmaterials and the insulating material. The operations of 1515 may beperformed according to the methods described herein.

At 1520, the method 1500 may include etching a second set of channelsalong a second direction into the layered assembly of materials tocreate a second set of sections of the second sacrificial material, thesecond set of channels extending through the first sacrificial materialand the second sacrificial material. The operations of 1520 may beperformed according to the methods described herein.

At 1525, the method 1500 may include depositing a second insulatingmaterial within each of the second set of channels. The operations of1525 may be performed according to the methods described herein.

At 1530, the method 1500 may include removing the first and secondsacrificial materials to form a set of cavities of the layered assemblyof materials. The operations of 1530 may be performed according to themethods described herein.

At 1535, the method 1500 may include depositing a memory material ontothe layered assembly of materials to at least partially fill the set ofcavities. The operations of 1535 may be performed according to themethods described herein.

In some examples, an apparatus as described herein may perform a methodor methods, such as the method 1500. The apparatus may include features,means, or instructions (e.g., a non-transitory computer-readable mediumstoring instructions executable by a processor) for etching a first setof channels along a first direction into a layered assembly of materialsto create a first set of sections of the layered assembly of materials,the layered assembly of materials including a first conductive materialand a first sacrificial material, depositing an insulating materialwithin each of the first set of channels, depositing a secondsacrificial material onto the first set of sections of the layeredassembly of materials and the insulating material, etching a second setof channels along a second direction into the layered assembly ofmaterials to create a second set of sections of the second sacrificialmaterial, the second set of channels extending through the firstsacrificial material and the second sacrificial material, depositing asecond insulating material within each of the second set of channels,removing the first and second sacrificial materials to form a set ofcavities of the layered assembly of materials, and depositing a memorymaterial onto the layered assembly of materials to at least partiallyfill the set of cavities. The apparatus may include, for example,physical vapor deposition equipment, chemical vapor depositionequipment, ion implantation equipment, etching (e.g., plasma etching,wet etching, dry etching) equipment, photolithography equipment (e.g.,photoresist application equipment, steppers), planarization (e.g.,chemical mechanical planarization) equipment, and the like.

Some examples of the method 1500 and the apparatus described herein mayfurther include operations, features, means, or instructions forremoving material from the layered assembly of materials afterdepositing the insulating material within each of the first set ofchannels to expose a surface of the first sacrificial material.

In some examples of the method 1500 and the apparatus described herein,the removing material includes chemical mechanical planarization.

Some examples of the method 1500 and the apparatus described herein mayfurther include operations, features, means, or instructions forremoving material from the layered assembly of materials afterdepositing the second insulating material within each of the second setof channels to expose a surface of the second sacrificial material.

In some examples of the method 1500 and the apparatus described herein,the removing material includes chemical mechanical planarization.

Some examples of the method 1500 and the apparatus described herein mayfurther include operations, features, means, or instructions fordepositing a second conductive material onto the memory material, wherethe second conductive material at least partially fills the second setof channels.

Some examples of the method 1500 and the apparatus described herein mayfurther include operations, features, means, or instructions fordepositing a first electrode material in a layer between the firstconductive material and the first sacrificial material, and depositing asecond electrode material onto the memory material before depositing thesecond conductive material.

In some examples of the method 1500 and the apparatus described herein,depositing the second electrode material may include operations,features, means, or instructions for performing a material removalprocess on the layered assembly of materials to expose the secondinsulating material.

In some examples of the method 1500 and the apparatus described herein,etching the first set of channels may include operations, features,means, or instructions for depositing a first mask material onto thefirst sacrificial material, and patterning the first mask materialaccording to a first pattern used to etch the first set of channels.

Some examples of the method 1500 and the apparatus described herein mayfurther include operations, features, means, or instructions forremoving the first mask material after depositing the insulatingmaterial within each of the first set of channels.

In some examples of the method 1500 and the apparatus described herein,etching the second set of channels may include operations, features,means, or instructions for depositing a second mask material onto thesecond sacrificial material, and patterning the second mask materialaccording to a second pattern used to each the second set of channels.

In some examples of the method 1500 and the apparatus described herein,the first direction may be orthogonal to the second direction.

In some examples of the method 1500 and the apparatus described herein,each of the set of cavities may be disposed between sections of theinsulating material and the second insulating material.

Some examples of the method 1500 and the apparatus described herein mayfurther include operations, features, means, or instructions for etchingexcess memory material after depositing the memory material to exposethe second set of channels.

In some examples of the method 1500 and the apparatus described herein,depositing the memory material may include operations, features, means,or instructions for selectively depositing the memory material withinthe set of cavities.

In some examples of the method 1500 and the apparatus described herein,the memory material includes a chalcogenide material.

Some examples of the method 1500 and the apparatus described herein mayfurther include operations, features, means, or instructions for etchingthe second set of channels divides the first sacrificial material of thefirst set of sections into a third set of sections.

FIG. 16 shows a flowchart illustrating a method or methods 1600 thatsupports techniques for forming self-aligned memory structures inaccordance with the present disclosure. The operations of method 1600may be implemented by a manufacturing system or one or more controllersassociated with a manufacturing. In some examples, one or morecontrollers may execute a set of instructions to control one or morefunctional elements of the manufacturing system to perform the describedfunctions. Additionally or alternatively, one or more controllers mayperform parts of the described functions using special-purpose hardware.

At 1605, the method 1600 may include forming a first set of sections ofa layered assembly of a first conductor material and a first sacrificialmaterial, the first set of sections elongated in a first dimension andseparated by a first insulating material. The operations of 1605 may beperformed according to the methods described herein.

At 1610, the method 1600 may include forming a second set of sections ofa second sacrificial material over the first set of sections of thelayered assembly and the first insulating material, the second set ofsections elongated in a second dimension and separated by a secondinsulating material. The operations of 1610 may be performed accordingto the methods described herein.

At 1615, the method 1600 may include replacing the first sacrificialmaterial in the first set of sections with a memory material. Theoperations of 1615 may be performed according to the methods describedherein.

At 1620, the method 1600 may include replacing the second sacrificialmaterial in the second set of sections with a second conductor material.The operations of 1620 may be performed according to the methodsdescribed herein.

In some examples, an apparatus as described herein may perform a methodor methods, such as the method 1600. The apparatus may include features,means, or instructions (e.g., a non-transitory computer-readable mediumstoring instructions executable by a processor) for forming a first setof sections of a layered assembly of a first conductor material and afirst sacrificial material, the first set of sections elongated in afirst dimension and separated by a first insulating material, forming asecond set of sections of a second sacrificial material over the firstset of sections of the layered assembly and the first insulatingmaterial, the second set of sections elongated in a second dimension andseparated by a second insulating material, replacing the firstsacrificial material in the first set of sections with a memorymaterial, and replacing the second sacrificial material in the secondset of sections with a second conductor material. The apparatus mayinclude, for example, physical vapor deposition equipment, chemicalvapor deposition equipment, ion implantation equipment, etching (e.g.,plasma etching, wet etching, dry etching) equipment, photolithographyequipment (e.g., photoresist application equipment, steppers),planarization (e.g., chemical mechanical planarization) equipment, andthe like.

In some examples of the method 1600 and the apparatus described herein,the first set of sections may be formed along a first direction, and thesecond set of sections may be formed along a second direction, differentfrom the second direction, such that the memory material may be disposedbetween two first insulating materials and two second insulatingmaterials.

In some examples of the method 1600 and the apparatus described herein,replacing the first sacrificial material with the memory material mayinclude operations, features, means, or instructions for removing thefirst sacrificial material and the second sacrificial material,depositing the memory material onto the layered assembly, and removingportions of the memory material to form sections of the memory materialhaving a same height as the first insulating material.

Some examples of the method 1600 and the apparatus described herein mayfurther include operations, features, means, or instructions for formingan electrode between the first conductor material and the firstsacrificial material.

In some examples of the method 1600 and the apparatus described herein,replacing the first sacrificial material with the memory material mayinclude operations, features, means, or instructions for removing thefirst sacrificial material and the second sacrificial material, andselectively depositing the memory material onto portions of the layeredassembly having the electrode exposed by removal of the firstsacrificial material and the second sacrificial material.

It should be noted that the methods described above describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Furthermore, portions from two or more of the methods may be combined.

An apparatus is described. The apparatus may include a set of memorycells formed by a process including, deposit an insulating materialwithin each of the first set of channels, deposit a second sacrificialmaterial onto the first set of sections of the layered assembly ofmaterials and the insulating material, etch a second set of channelsalong a second direction into the layered assembly of materials tocreate a second set of sections of the second sacrificial material, thesecond set of channels extending through the first sacrificial materialand the second sacrificial material, deposit a second insulatingmaterial within each of the second set of channels, remove the first andsecond sacrificial materials to form a set of cavities of the layeredassembly of materials, and deposit a memory material onto the layeredassembly of materials to at least partially fill the set of cavities.

In some examples, the process further may include operations, features,means, or instructions for depositing an electrode material onto thelayered assembly of materials after depositing the memory material, theelectrode material forming a layer over the memory material and thesecond insulating material.

In some examples, the process further may include operations, features,means, or instructions for removing a portion of the layer of theelectrode material disposed over a top surface of the second insulatingmaterial to expose the top surface of the second insulating material.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof. Some drawings may illustrate signals as a single signal;however, it will be understood by a person of ordinary skill in the artthat the signal may represent a bus of signals, where the bus may have avariety of bit widths.

The terms “electronic communication,” “conductive contact,” “connected,”and “coupled” may refer to a relationship between components thatsupports the flow of signals between the components. Components areconsidered in electronic communication with (or in conductive contactwith or connected with or coupled with) one another if there is anyconductive path between the components that can, at any time, supportthe flow of signals between the components. At any given time, theconductive path between components that are in electronic communicationwith each other (or in conductive contact with or connected with orcoupled with) may be an open circuit or a closed circuit based on theoperation of the device that includes the connected components. Theconductive path between connected components may be a direct conductivepath between the components or the conductive path between connectedcomponents may be an indirect conductive path that may includeintermediate components, such as switches, transistors, or othercomponents. In some cases, the flow of signals between the connectedcomponents may be interrupted for a time, for example, using one or moreintermediate components such as switches or transistors.

The term “coupling” refers to condition of moving from an open-circuitrelationship between components in which signals are not presentlycapable of being communicated between the components over a conductivepath to a closed-circuit relationship between components in whichsignals can be communicated between components over the conductive path.When a component, such as a controller, couples other componentstogether, the component initiates a change that allows signals to flowbetween the other components over a conductive path that previously didnot permit signals to flow.

The term “isolated” refers to a relationship between components in whichsignals are not presently capable of flowing between the components.Components are isolated from each other if there is an open circuitbetween them. For example, two components separated by a switch that ispositioned between the components are isolated from each other when theswitch is open. When a controller isolates two components from oneanother, the controller affects a change that prevents signals fromflowing between the components using a conductive path that previouslypermitted signals to flow.

The term “layer” used herein refers to a stratum or sheet of ageometrical structure. Each layer may have three dimensions (e.g.,height, width, and depth) and may cover at least a portion of a surface.For example, a layer may be a three-dimensional structure where twodimensions are greater than a third, e.g., a thin-film. Layers mayinclude different elements, components, and/or materials. In some cases,one layer may be composed of two or more sublayers. In some of theappended figures, two dimensions of a three-dimensional layer aredepicted for purposes of illustration.

As used herein, the term “substantially” means that the modifiedcharacteristic (e.g., a verb or adjective modified by the termsubstantially) need not be absolute but is close enough to achieve theadvantages of the characteristic.

As used herein, the term “electrode” may refer to an electricalconductor, and in some cases, may be employed as an electrical contactto a memory cell or other component of a memory array. An electrode mayinclude a trace, wire, conductive line, conductive layer, or the likethat provides a conductive path between elements or components of memoryarray.

The term “photolithography,” as used herein, may refer to the process ofpatterning using photoresist materials and exposing such materials usingelectromagnetic radiation. For example, a photoresist material may beformed on a base material by, for example, spin-coating the photoresiston the base material. A pattern may be created in the photoresist byexposing the photoresist to radiation. The pattern may be defined by,for example, a photo mask that spatially delineates where the radiationexposes the photoresist. Exposed photoresist areas may then be removed,for example, by chemical treatment, leaving behind the desired pattern.In some cases, the exposed regions may remain, and the unexposed regionsmay be removed.

Similarly, as used in the present disclosure, the terms “orthogonal” and“perpendicular,” when used to describe geometric relationships, are notintended to suggest a limitation to precise geometric perpendicularity.For instance, the terms “orthogonal” and “perpendicular” as used in thepresent disclosure are intended to include typical deviations fromgeometric perpendicularity relating to such considerations as, forexample, manufacturing and assembly tolerances. Further, certainmanufacturing process such as molding, casting, depositing, and etching,may include or result in positive or negative drafting, edge chamfersand/or fillets, or other features to facilitate any of themanufacturing, assembly, or operation of various components, in whichcase certain surfaces may not be geometrically perpendicular, but may beperpendicular in the context of the present disclosure.

The devices discussed herein, including a memory array, may be formed ona semiconductor substrate, such as silicon, germanium, silicon-germaniumalloy, gallium arsenide, gallium nitride, etc. In some cases, thesubstrate is a semiconductor wafer. In other cases, the substrate may bea silicon-on-insulator (SOI) substrate, such as silicon-on-glass (SOG)or silicon-on-sapphire (SOP), or epitaxial layers of semiconductormaterials on another substrate. The conductivity of the substrate, orsub-regions of the substrate, may be controlled through doping usingvarious chemical species including, but not limited to, phosphorous,boron, or arsenic. Doping may be performed during the initial formationor growth of the substrate, by ion-implantation, or by any other dopingmeans.

A switching component or a transistor discussed herein may represent afield-effect transistor (FET) and comprise a three terminal deviceincluding a source, drain, and gate. The terminals may be connected toother electronic elements through conductive materials, e.g., metals.The source and drain may be conductive and may comprise a heavily-doped,e.g., degenerate, semiconductor region. The source and drain may beseparated by a lightly-doped semiconductor region or channel. If thechannel is n-type (i.e., majority carriers are electrons), then the FETmay be referred to as a n-type FET. If the channel is p-type (i.e.,majority carriers are holes), then the FET may be referred to as ap-type FET. The channel may be capped by an insulating gate oxide. Thechannel conductivity may be controlled by applying a voltage to thegate. For example, applying a positive voltage or negative voltage to ann-type FET or a p-type FET, respectively, may result in the channelbecoming conductive. A transistor may be “on” or “activated” when avoltage greater than or equal to the transistor's threshold voltage isapplied to the transistor gate. The transistor may be “off” or“deactivated” when a voltage less than the transistor's thresholdvoltage is applied to the transistor gate.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details toproviding an understanding of the described techniques. Thesetechniques, however, may be practiced without these specific details. Insome instances, well-known structures and devices are shown in blockdiagram form to avoid obscuring the concepts of the described examples.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but in the alternative, the processor may be any processor, controller,microcontroller, or state machine. A processor may also be implementedas a combination of computing devices (e.g., a combination of a DSP anda microprocessor, multiple microprocessors, one or more microprocessorsin conjunction with a DSP core, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items (for example, a list of items prefaced by a phrasesuch as “at least one of” or “one or more of”) indicates an inclusivelist such that, for example, a list of at least one of A, B, or C meansA or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, asused herein, the phrase “based on” shall not be construed as a referenceto a closed set of conditions. For example, an exemplary step that isdescribed as “based on condition A” may be based on both a condition Aand a condition B without departing from the scope of the presentdisclosure. In other words, as used herein, the phrase “based on” shallbe construed in the same manner as the phrase “based at least in parton.”

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be apparent to those skilled in the art, and the generic principlesdefined herein may be applied to other variations without departing fromthe scope of the disclosure. Thus, the disclosure is not limited to theexamples and designs described herein but is to be accorded the broadestscope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method, comprising: etching a first pluralityof channels along a first direction into a layered assembly of materialsto create a first plurality of sections of the layered assembly ofmaterials, the layered assembly of materials comprising a firstconductive material, an electrode material, and a first sacrificialmaterial positioned above and in direct contact with the electrodematerial; depositing a first insulating material within each of thefirst plurality of channels; depositing a second sacrificial materialonto the first plurality of sections of the layered assembly ofmaterials and the first insulating material; etching a second pluralityof channels along a second direction into the layered assembly ofmaterials to create a second plurality of sections of the secondsacrificial material, the second plurality of channels extending throughthe first sacrificial material and the second sacrificial material;depositing a second insulating material within each of the secondplurality of channels; removing the first and second sacrificialmaterials to form a plurality of cavities of the layered assembly ofmaterials, each cavity extending down to a top surface of the electrodematerial and at least partially bounded by the first insulating materialwhere the first insulating material abuts the top surface of theelectrode material; and depositing a memory material onto the layeredassembly of materials to at least partially fill the plurality ofcavities, such that a bottom surface of the memory material extends froma first side surface of the first insulating material to a second sidesurface of the first insulating material, the second side surfaceopposing the first side surface.
 2. The method of claim 1, furthercomprising: removing material from the layered assembly of materialsafter depositing the first insulating material within each of the firstplurality of channels to expose a surface of the first sacrificialmaterial.
 3. The method of claim 2, wherein removing the materialcomprises chemical mechanical planarization.
 4. The method of claim 1,further comprising: removing material from the layered assembly ofmaterials after depositing the second insulating material within each ofthe second plurality of channels to expose a surface of the secondsacrificial material.
 5. The method of claim 4, wherein removing thematerial comprises chemical mechanical planarization.
 6. The method ofclaim 1, further comprising: depositing a second conductive materialonto the memory material, wherein the second conductive material atleast partially fills the second plurality of channels.
 7. The method ofclaim 6, wherein the electrode material is positioned in a layer betweenthe first conductive material and the first sacrificial material in thelayered assembly of materials; and the method further comprisingdepositing a second electrode material onto the memory material beforedepositing the second conductive material.
 8. The method of claim 7,wherein depositing the second electrode material comprises depositingthe second electrode material over the memory material and the secondinsulating material, the method further comprising: performing amaterial removal process on the layered assembly of materials to exposethe second insulating material.
 9. The method of claim 1, whereinetching the first plurality of channels comprises: depositing a firstmask material onto the first sacrificial material; and patterning thefirst mask material according to a first pattern used to etch the firstplurality of channels.
 10. The method of claim 9, further comprising:removing the first mask material after depositing the first insulatingmaterial within each of the first plurality of channels.
 11. The methodof claim 9, wherein etching the second plurality of channels comprises:depositing a second mask material onto the second sacrificial material;and patterning the second mask material according to a second patternused to etch the second plurality of channels.
 12. The method of claim1, wherein the first direction is orthogonal to the second direction.13. The method of claim 1, wherein each of the plurality of cavities isdisposed between sections of the first insulating material and thesecond insulating material.
 14. The method of claim 1, furthercomprising: etching excess memory material after depositing the memorymaterial to expose the second plurality of channels.
 15. The method ofclaim 1, wherein depositing the memory material comprises: selectivelydepositing the memory material within the plurality of cavities.
 16. Themethod of claim 1, wherein the memory material comprises a chalcogenidematerial.
 17. The method of claim 1, wherein: etching the secondplurality of channels divides the first sacrificial material of thefirst plurality of sections into a third plurality of sections.
 18. Anapparatus, comprising: a plurality of memory cells formed by a processcomprising: etching a first plurality of channels along a firstdirection into a layered assembly of materials to create a firstplurality of sections of the layered assembly of materials, the layeredassembly of materials comprising a first conductive material, anelectrode material, and a first sacrificial material positioned aboveand in direct contact with the electrode material; depositing a firstinsulating material within each of the first plurality of channels;depositing a second sacrificial material onto the first plurality ofsections of the layered assembly of materials and the first insulatingmaterial; etching a second plurality of channels along a seconddirection into the layered assembly of materials to create a secondplurality of sections of the second sacrificial material, the secondplurality of channels extending through the first sacrificial materialand the second sacrificial material; depositing a second insulatingmaterial within each of the second plurality of channels; removing allof the first and second sacrificial materials to form a plurality ofcavities of the layered assembly of materials, each cavity extendingdown to a top surface of the electrode material and at least partiallybounded by the first insulating material where the first insulatingmaterial abuts the top surface of the electrode material; and depositinga memory material onto the layered assembly of materials to at leastpartially fill the plurality of cavities, such that a bottom surface ofthe memory material extends from a first side surface of the firstinsulating material to a second side surface of the first insulatingmaterial, the second side surface opposing the first side surface. 19.The apparatus of claim 18, wherein the process further comprises:depositing a second electrode material onto the layered assembly ofmaterials after depositing the memory material, the second electrodematerial forming a layer over the memory material and the secondinsulating material.
 20. The apparatus of claim 19, wherein the processfurther comprises: removing a portion of the layer of the secondelectrode material disposed over a top surface of the second insulatingmaterial to expose the top surface of the second insulating material.21. A method, comprising: forming a first plurality of sections of alayered assembly of a first conductor material, an electrode material,and a first sacrificial material positioned above and in direct contactwith the electrode material, the first plurality of sections elongatedin a first dimension and separated by a first insulating material;forming a second plurality of sections of a second sacrificial materialover the first plurality of sections of the layered assembly and thefirst insulating material, the second plurality of sections elongated ina second dimension and separated by a second insulating material;replacing the first sacrificial material in the first plurality ofsections with a memory material, the replacing comprising depositing thememory material in contact with the first insulating material and thesecond insulating material, such that a bottom surface of the memorymaterial extends from a first side surface of the first insulatingmaterial to a second side surface of the first insulating material, thesecond side surface opposing the first side surface; and replacing thesecond sacrificial material in the second plurality of sections with asecond conductor material.
 22. The method of claim 21, wherein: thefirst plurality of sections are formed along a first direction; and thesecond plurality of sections are formed along a second direction,different from the first direction, such that the memory material isdisposed between two first insulating materials and two secondinsulating materials.
 23. The method of claim 21, wherein replacing thefirst sacrificial material with the memory material comprises: removingthe first sacrificial material and the second sacrificial material;depositing the memory material onto the layered assembly; and removingportions of the memory material to form sections of the memory materialhaving a same height as the first insulating material.
 24. The method ofclaim 21, wherein the electrode material is between the first conductormaterial and the first sacrificial material in the layered assembly. 25.The method of claim 24, wherein replacing the first sacrificial materialwith the memory material comprises: removing the first sacrificialmaterial and the second sacrificial material; and selectively depositingthe memory material onto portions of the layered assembly having theelectrode material exposed by removal of the first sacrificial materialand the second sacrificial material.